The present invention relates generally to devices for increasing the traction between a vehicle wheel and a supporting surface. More particularly, the present invention concerns an improved assembly for quickly and easily attaching a snow chain to a vehicular wheel and tire assembly.
In those climates where a significant snowfall occurs during the winter months, snow accumulations frequently become packed on road or highway surfaces causing slippery hazardous driving conditions. Driving conditions can also be dangerous when rain falls during the cold season and ice forms on highway surfaces. The effects of ice and accumulated snow on the traction between a vehicle tire and the road surface are well known. In fact, it is widely recognized that snow chains provide the best means for significantly increasing the traction between the vehicle tire and the road surface during such slippery conditions.
The early designs for traction enhancing tire chains include a pair of generally parallel side chains having a plurality of cross-chains extending between the side chains. The side chains are disposed one on each side of the tire. When the ends of each side chain are connected to one another, there is an endless chain on both the inside and outside of the wheel assembly with the cross-chains extending across the load bearing surface of the wheel assembly.
Such chains are difficult for drivers or vehicle operators to install. For example, it is often necessary or desirable to elevate the wheel assembly off the ground so that the two ends of each side chain can be easily connected together. If the vehicle is not elevated, it then becomes necessary to reach around the tire with both hands in order to grasp and manipulate the two free ends into their connecting arrangement. The outside chain, i.e., on the readily accessible side of the wheel assembly, can be fairly easily connected once the inside chain is secured. Since the chains are necessarily heavy and sometimes requires manipulation in order to distribute the cross-links around the circumference of the wheel assembly, such an arrangement requires manual dexterity in the individual installing the chains and preferably some degree of experience.
During operation of these chains, there is no connection between the chain and the wheel assembly itself. Thus, and, under some circumstances, the chain itself is free to slip relative to the wheel assembly. More significantly, if a side chain should break, the entire chain may be lost.
Another type of chain assembly is also available in which each of a plurality of cross-chains is provided with a substantially inextensible strap and buckle connection for the ends. To install these cross-chains, it is necessary to thread one end of the strap through an aperture in the wheel assembly and connect the other end to the strap. This arrangement is objectionable for several reasons. It is possible for the chain to move relative to the tire assembly in a direction circumferential to a radial cross-section of the tire. Moreover, the number of cross-chains is limited by the number of available apertures in the wheel assembly. Accordingly, a limited amount of traction is available. In addition, the straps are abraded by the aperture edges. Thus, the straps can be weakened to such a degree that they sever and the cross chain is lost. Certainly, such cross-chains are unsuitable for prolonged use.
Another problem with the conventionally available chain assemblies is the lack of universality. More particularly, since different wheel and tire sizes give rise to different tread widths and different tire circumferential lengths, tire chains must be stocked in a variety of nominal sizes to permit use with the wide variety of tires used on domestic, foreign and commercial vehicles. This problem is particularly important to the retail outlets which stock the chains for resale to consumers.
In view of the foregoing discussion, it is apparent that the need continues to exist for an easily attached cross-chain assembly which overcomes problems of the type discussed above.